John Gill Commentary 2 Samuel 2:28

"So Joab blew the trumpet; and all the people stood still, and pursued after Israel no more, neither fought they any more." — 2 Samuel 2:28 (ASV)

So Joab blew a trumpet ;

Or caused one to be blown as a signal of a retreat:

and all the people stood still, and pursued after Israel no more ;

as soon as they heard the trumpet sound, the meaning of which they understood, they stepped at once, and left off their pursuit:

neither fought they any more ;

that day, and perhaps no pitched battle afterwards; for none we read of, though the war continued after this a long time, and there might be often skirmishes, which greatly weakened Abner's party. See (2 Samuel 3:1) .